The invention relates to a backing for tufted carpets as are typically used in the living room and in the furnished area. According to DE-A1-39 41 189, such backings consist of a non-woven, spunbonded material of polyester and copolyester filaments which are irregularly joined and autogenously, thermally agglutinated during their formation and bonding. This document addresses the problem that high mechanical and thermal stresses occur when manufacturing and processing a tufted carpet which lead to unwanted deformations. These are, in particular, elongations in the lengthwise direction and shortenings in the transverse direction. There should also be great dimensional stability when laying or during ageing. This holds true in particular for backings or underlays having low weight equal to or below 150 g/m.sup.2.
The manufacture of tuft backings is explained in DE-A-39 41 189 as well. For example, a molten, synthetic mass of polyester, in particular polyethylene terephthalate or polyethylene terephthalate/polybutylene terephthalate, is extruded in the form of continuous filaments or bicomponent filaments. These filaments are bonded by needling and thermobonding. Lightweight, spunbonded materials are formed of between 20 and 500 g/m.sup.2, preferably under 150 g/m.sup.2. At the same time, the titers of the filaments are about 7 dtex.
In the interest of stabilizing these spunbonded materials, for example, polyester filaments are applied in the lengthwise direction on one or both of their sides. These filaments run straight, parallel to one another and exist as continuous, high-modulus filaments. Understood under the last term is a modulus of elasticity over 20 GPa, at room temperature and at temperatures over 200.degree. C., as well. The high-modulus filaments are secured to the formed fabric by means of special needling during or after the formation of the nonwoven fabric, starting from warp beams, with travelers or bobbins. The parallel-running, high-modulus filaments have titers of 0.28 to 27.2 dtex. Their distances from one another are 2 to 30 mm. It is suggested to apply such a quantity of filaments that, given stretching of the formed fabric in the lengthwise direction, a tearing is first determined from 80 daN/m width. Glass filaments are named as preferred high- modulus threads.
DE-U1-295 09 066 describes a textile composite material for stabilizing floors and ground cover! layers and as a load-absorbing filtration layer. In this case, the composite material consists of a formed fabric of plastic fibers. To attain high resistance to tearing in the main load direction without excessive stretching, and to absorb great tensile forces, exclusively parallel-running, load-absorbing, straight, plastic, continuous filaments are rascheled on the nonwoven fabric. Due to this, the textile composite material of nonwoven fabric becomes highly tear-resistant in the main load direction. The plastic, continuous filaments counteract an application of force immediately, without having to be substantially stretched beforehand.
The load-absorbing threads are applied with a width on the non-woven fabric corresponding to the width of the formed-fabric web. Their cross-section lies in the range of 2 to 100 mm.sup.2, their distance to one another is 1 to 100 mm. For example, polyester fibers form the base nonwoven fabric which contains the load-absorbing, parallel filaments rascheled on one or both of its sides. A thin binding yarn is guided as a knitting chain on the raschel machine and secures the load-absorbing, plastic, continuous filaments on the nonwoven fabric.
In one preferred specific embodiment, the load-absorbing filaments run warpwise and in the lengthwise direction of the nonwoven fabric web. Another variant is indicated in which, in each case, the load-absorbing filaments are rascheled in pairs on the nonwoven fabric, the distance to the thread pairs being 1 to 100 mm. In each case, polypropylene is specified as the preferred material for the nonwoven fabric, load-absorbing filaments and binding yarn.